Replace macOS High Sierra with Mojave (#10776)
Replace macOS High Sierra with Mojave (#10776)

Given Catalina was just released, and High Sierra is now 2 years old, I think we should at least be targeting Mojave
yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli,yugangw-msft/azure-cli